JP3663302B2 - Magnetic disk unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic disk device that stops the rotation of a spindle motor in order to reduce power consumption, and more particularly, to a magnetic disk device that shortens the return time from a stopped state of the spindle motor.
[0002]
[Prior art]
A magnetic disk device moves a head in a radial direction with respect to a rotating disk, accurately positions a target data track, and records and reproduces information magnetically. FIG. 1 is a cross-sectional view illustrating a schematic configuration of a typical magnetic disk device. In this example, six heads 11, three disks 12, and a rotary actuator 13 which are mechanical parts of the magnetic disk device are housed in an enclosure. The head 11 is supported by a rotary actuator 13 driven by a voice coil motor 14, and performs recording / reproduction on each of the six surfaces of the disk 12. A package board 17 constituting a main part of an electronic circuit for controlling the magnetic disk device is disposed outside the enclosure.
[0003]
FIG. 2 is a plan view showing a schematic configuration in the enclosure of the magnetic disk apparatus. The disk 12 rotates in one direction around the point A in the direction indicated by the arrow at a speed of several thousand revolutions per minute. The rotary actuator 13 is driven by a voice coil motor to reciprocate around the point B, and can move the head 11 in the radial direction of the disk 12 as indicated by an arrow. In the figure, a recording / reproducing amplifier 15 of a head, which is a part of an electronic circuit not arranged on the package board 17, is shown.
[0004]
A schematic view of a part of this apparatus as seen from above is shown in FIG. Special magnetization information called servo information representing head position information is written on the magnetic disk 12 before shipment from the factory. The power applied to the voice coil motor is adjusted based on this position information, and the head 11 is accurately positioned with respect to the target track 16 via the rotary actuator 13. Positioning the head with respect to the target track is called a following operation, and information is recorded and reproduced magnetically while performing the following operation. In FIG. 3, the track 16 is indicated by a solid line, but the track 16 is formed of magnetic information and cannot be directly recognized optically. In practice, since 10,000 or more tracks 16 can be formed on the disk, there are tracks that are much denser than the image shown in FIG.
[0005]
The operation of stopping the rotation of the spindle motor for the purpose of reducing the power consumption of the magnetic disk is widely adopted particularly in portable computers. For example, in an ATA interface standard defined by ANSI X39.2, a function called an automatic power down sequence is adopted as a standard. This is because if the data transfer request is not generated within the time set by the user in advance in the standby timer, the spindle motor is automatically stopped and the power consumption is reduced to wait for the next data transfer request. It is a function. FIG. 4 is an explanatory diagram of the automatic power down sequence. When the host machine issues a command issuance 35 to the magnetic disk device in the standby state 40 with the rotation of the disk stopped, the magnetic disk device performs the disk activation start 30. The time for increasing the rotation of the disk is the processing waiting time 37, and the subsequent disk activation completion 31 is called an active state 41. Since the magnetic disk device can perform data reproduction or recording operation only in the active state 41, the command issued from the host machine is executed at the processing time 38 in the figure. If the host machine does not issue an instruction from the immediately preceding instruction issuance 35 during the standby timer setting time, it transits from the disk stop start 32 to the standby state 42 again through the disk stop completion 33. The next command issuance 36 shifts to the disk start start 34 and repeats the same operation as described above. The processing from the command issuance 35 to the processing waiting time 37 and the processing time 38 will be described in more detail with reference to FIG. In the initial process 52 immediately after receiving the reproduction command issue 51 from the host machine, the interface circuit interprets the command, starts the system clock, and starts the microprocessor. After this, the disk startup start 68 is started when power is supplied to the spindle motor. After the disk activation process 53 and the disk activation completion 69, the process proceeds to the external force measurement 54. The external force measurement 54 is a process necessary to correct the external force applied to the actuator and perform a seek accurately. The main factor of the external force is the non-uniformity of the magnetic field of the magnet and the wiring to the head and voice coil motor mounted on the actuator. Since these external forces are strongly influenced by the angle and temperature of the actuator, it is preferable to measure them frequently in the environment in which they are used. In actual measurement, a method that repeats empty seeks called dummy seeks several times at different radial positions on the disk is often used, and is usually performed not only at startup but also at regular intervals. . After the external force measurement is completed, a seek 55 to the target track is performed. After the completion of the seek is confirmed, an actual reproduction process 56 is performed, and the reproduction command ends 57. The processing from the recording command issuance 61 to the recording command end 67 is the same as the processing from the reproducing command issuance 51 to the reproducing command end 57 described above.
[0006]
The time from the execution of the reproduction command issuance 51 or the recording command issuance 61 to the magnetic disk device in the standby state until the reproduction processing end processing 56 or the recording command end 66 is the actual processing time of the reproduction processing 56 or the recording processing 66. Rather than the disk activation process 53 or the disk activation process 63. A magnetic disk device using a glass disk with a diameter of about 63 mm intended to be mounted on a portable PC was used to measure the time of data reproduction processing 56 or recording processing 66 of 256 sectors. 30 ms. Further, when the time of the disk activation processing 53 or the disk 63 was measured, both were about 1500 ms, which is substantially the same time.
[0007]
[Problems to be solved by the invention]
In order to return the magnetic disk device in the standby state to the active state, it takes a long time to start the disk. For this reason, when the automatic power-down sequence functions to stop the spindle motor, even when a recording command or a playback command with a small number of sectors is processed, time is required in units of seconds, and the access performance of the apparatus is significantly deteriorated. There was a problem. In view of the access performance of the magnetic disk device, it is preferable that the disk startup time is as short as possible. The shortening of the disk startup time can be realized by increasing the electric power supplied to the spindle motor or by setting the steady rotation speed of the disk low. However, in portable PCs, the upper limit of the power consumed by the magnetic disk device is often limited, and the current power to the spindle motor cannot be increased. Further, from the viewpoint of the data transfer speed of the magnetic disk device, the higher the steady rotational speed of the disk, the better.
[0008]
In order to achieve both reduction in power consumption and improvement in access performance of magnetic disk devices, the use of small diameter disks with a diameter of 48 mm or less, and thin disks with a thickness of 0.5 mm or less, the moment of inertia and rotation of the disk. There are ways to reduce the amount of energy lost. With these technologies, the startup time of the disk is greatly shortened, so even if the disk rotation is stopped frequently, the adverse effect on the access performance is reduced, and it can be very effective in reducing power consumption. it can. However, such a reduction in the diameter and thickness of the disk has the great disadvantage that the storage capacity is reduced due to the reduction in the data area and the deterioration of the head positioning accuracy.
[0009]
From these viewpoints, there has been a demand for a technology that improves the access performance and does not decrease the conventional storage capacity while reducing the power consumption of the magnetic disk device by the standby function.
[0010]
[Means for Solving the Problems]
The above-mentioned problem is that the magnetic disk device in a state where the spindle motor is stopped takes a shorter time from receiving the data reproduction command or recording command to finishing the processing of the command than the recording command in the reproduction command. By using, it is possible to improve the access performance when executing the reproduction instruction and solve the problem. At this time, when the magnetic disk device in a state where the spindle motor is stopped receives the data reproduction command, it receives the data recording command using the initial value stored in the semiconductor memory in advance as the external force correction value for the seek operation. In some cases, by using a technique for measuring the external force correction value of the seek operation using a dummy seek, it is possible to further improve the performance performance when a reproduction command is received. At this time, a non-volatile RAM is provided in the enclosure, and replacement of the package board is performed by periodically measuring and rewriting the external force correction value of the seek operation as a different parameter for each magnetic disk device. Can be made easier. At this time, an element for temperature measurement is provided in the enclosure, and the seek operation is detected in the change in the external force correction value caused by the temperature by calculating the external force correction value of the seek operation based on the temperature data output from this element. Can be less affected. At this time, by using a serial transfer method for data input / output of the nonvolatile RAM and temperature measuring element, the number of connection terminals to the package board can be reduced, and an inexpensive connector portion can be used.
[0011]
The above problem is that the magnetic disk device with the spindle motor stopped selects the mode 1 steady rotation speed when receiving a data reproduction command, and mode 2 steady rotation when receiving a data recording command. By selecting the speed and making the rotation speed of mode 1 lower than the rotation speed of mode 2, the problem can be solved by improving the access performance at the time of executing the reproduction command. At this time, by making the rotational acceleration during the transition from the rotational speed of mode 1 to the rotational speed of mode 2 smaller than the rotational acceleration at the time of rising from the rotational stop state to the rotational speed of mode 1 or mode 2 Since the data reproduction operation can be performed during the transition period from the mode 1 to the mode 2, the access performance at the time of executing the reproduction instruction can be further improved. At this time, by changing the clock frequency of the microprocessor or hard disk controller in accordance with the number of rotations of the spindle motor during the period of transition from the rotational speed of mode 1 to the rotational speed of mode 2, it is easier to switch from mode 1 to mode 1. The reproduction operation in the transition period to 2 can be realized.
[0012]
Further, the above problem is that when the magnetic disk device in a state where the measured value spindle motor is stopped receives the data reproduction command, the initial value stored in the semiconductor memory in advance as the external force correction value of the seek operation is used. When a recording command is received, it is possible to solve the problem by improving performance performance when a reproduction command is received by using a technique for measuring the external force correction value of the seek operation using a dummy seek.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
<Example 1>
The basic configuration of the magnetic disk apparatus of the present invention is almost the same as that described in the section of the prior art with reference to FIG. 1, FIG. 2 and FIG. Furthermore, a function of automatically shifting to the standby state and reducing the average power consumption shown in FIG. 4 as a conventional technique is also provided.
[0014]
Embodiments and features will be described with reference to FIG. 6 showing an example of the present invention, from the time when a magnetic disk device in a standby state receives a reproduction or recording command to the end of the reproduction or recording operation. . The horizontal axis in the figure is the time axis, and before time 0, the disk is stopped because the magnetic disk device is in the standby state, and its rotation speed is 0 RPM. FIG. 7 is a flowchart in which the processing of each process executed by the microprocessor is branched and displayed by the recording operation and the reproducing operation.
[0015]
When the recording command issuance 71 is performed at time 0, the disk activation start 73 is performed after a short initial process 72 (Step 2 in FIG. 7). The disk activation process 73 is from the disk activation start 88 (Step 3 in FIG. 7) to the disk activation completion 89 in which the determination of whether or not the disk rotation speed has reached the steady rotation speed of 4200 RPM (Step 4 in FIG. 7) ends. In addition, the magnetic disk device used for the prototype requires about 1.5 seconds (1500 ms). Next, in the external force measurement 74 (Step 6 in FIG. 7), the dummy seek is repeated in order to increase the head settling accuracy. This external force measurement requires about 0.5 seconds (500 ms). After this, seek 75 (Step 8 in FIG. 7) is performed, and after confirming that the head settling for the target data track has been completed (Step 9 in FIG. 7), recording process 76 (Step 10 in FIG. 7) is performed. . At this time, the time from the recording command issue 71 to the recording command end 77 was about 2.1 seconds.
[0016]
Next, the process of the reproduction command issue 81 will be described. The steps of the initial process 82 and the disk activation process 83 until the disk activation completion 89 are substantially the same as those for the recording command issue 71. However, unlike the recording command issuance 81, the initial parameter is read from the memory as a correction value without performing the external force measurement (Step 7 in FIG. 7), and the time related to the external force measurement is made from the time of the recording command issuance 71. Could also be shortened. Next, in the seek 85 (Step 8 in FIG. 7), a technique for making the slice for determining the end of the head settling with respect to the target data track (Step 9 in FIG. 7) wider than the seek 75 when the recording command issuance 71 is issued. Using. As a result, the seek 85 time could be kept equal to the seek 75 while using the initial parameter for the external force correction value. The time required for the reproduction process 86 (Step 10 in FIG. 7) was almost the same as the time required for the recording process 76. The time from the reproduction command issue 81 to the reproduction command end 87 at this time is about 1.6 seconds, which is shorter than 2.1 seconds at the time of the recording command issue 71.
[0017]
According to the present invention, the access performance when the automatic power-down sequence is adopted can be improved when the reproduction command is issued than when the recording command is issued, and a magnetic disk device that achieves both low power consumption and high access performance is provided. Could be realized.
[0018]
<Example 2>
The configuration of the second embodiment of the magnetic disk apparatus of the present invention will be described. The basic configuration is almost the same as that described in the section of the prior art, but in this embodiment, as shown in FIG. 8, the non-volatile RAM 130 is positioned adjacent to the head amplifier 15 for temperature measurement. The element 131 is mounted near the rotation center of the rotary actuator. Although the non-volatile RAM 130 can be mounted on a package board, the main purpose is to store different external force correction values for individual devices. For this reason, when considering the production management process in the factory, if the nonvolatile RAM 130 is arranged in the enclosure, the external force correction value can be measured and written in the process before the combination with the package board, and the productivity is improved. . The temperature measuring element 131 can also be mounted on the package board. However, since the main purpose is to calculate the external force correction value from the measured temperature, the rotary actuator 13 is most likely to affect the external force value. The effect of measuring the temperature in the vicinity of is high. If possible, it is desirable to arrange it near the center of rotation so as not to increase the rotational moment of the actuator.
[0019]
The nonvolatile RAM 130 or the temperature measuring element 131 is mounted in the enclosure, but is directly controlled by the microprocessor on the package board as shown in the block diagram of FIG. This is somewhat different from the control method in that the spindle motor and the voice coil motor 14 are connected via an amplifier and the head amplifier 15 is connected via a signal processing circuit and a hard disk controller. Therefore, digital transfer is possible for data transfer between the nonvolatile RAM 130 or the temperature measuring element 131 and the microprocessor, and the digital transfer method is also adopted in this embodiment in order to reduce the influence of external noise. doing. Furthermore, in order to reduce the number of control lines, as shown in FIG. 12, digital data is transferred by a serial method. Data is written from the microprocessor to the nonvolatile RAM 130 in synchronization with the rising edge of the clock started after the write gate signal is enabled, and then an 8-bit address (A3 in the example in FIG. 12), Bit data (C9 in the example in FIG. 12) can be transferred. Further, when reading data from the nonvolatile RAM 130 or the temperature measuring element 131 to the microprocessor, an 8-bit address (A3 in the example in FIG. 12) is synchronized with the rising edge of the clock after the read gate signal is enabled. After being sent from the microprocessor, data can be received in synchronization with the falling edge of the clock. Note that the parallel transfer method is possible if there is a margin in the arrangement of the connector with the package board, but there is a problem of an increase in cost due to an increase in the size of the connector.
[0020]
In the magnetic disk device of this embodiment, the external force correction value is measured in advance at the factory and recorded in the nonvolatile RAM 130. Since the reproduction process has a wider tolerance for the seek operation than the recording process, the access performance can be improved by reading and using the value measured in advance from the nonvolatile RAM 130 without measuring the external force correction value. . Since the external force correction value is strongly influenced by temperature, it is desirable to measure the initial value at various different temperatures, but it is not realistic to measure the external force correction value over a wide temperature range in the factory. . For this reason, the magnetic disk apparatus of this embodiment has a function of automatically measuring an external force correction value that changes depending on various temperature conditions by the processing shown in the flowchart of FIG. The microprocessor timer is reset (Step 1), and an access request from the host machine is checked (Step 2). If the timer value has reached the set value (Step 3), the external force correction value is measured by dummy seek (Step 4), and at the same time, temperature data is read from the temperature measuring element 131 (Step 5). Then, the external force correction value table in the nonvolatile RAM 130 is updated (Step 6). Since the set value of the Step 3 timer is set to about 1 minute in the prototype device, the external force and temperature are measured at intervals of about 1 minute.
[0021]
An example of the external force correction value table of the nonvolatile RAM 130 is shown in FIG. The temperature range from 0 ° C. to 70 ° C. is classified into 7 groups every 10 ° C. Further, it is possible to record data of external force correction values corresponding to the 17 radial positions of the disk by cylinder number for each temperature group. The external force correction value measured in FIG. 10 updates the table data corresponding to the temperature data and the measured cylinder number. A method for calculating the external force correction value from this table is also shown in FIG. Description will be made assuming that the measured temperature data is 18 ° C. and the seek destination cylinder number is 2600. First, a group having a temperature range of 10 to 20 ° C. is referred to from the external force correction value table, and data corresponding to cylinders 2000 and 3000, +19 and +13, are read out from the group. Since the target cylinder number is 2600, by interpolating the data of these two points, data +15 is calculated and used as a seek parameter. In the magnetic disk apparatus of this embodiment, the seek operation is less affected by the change in the external force correction value caused by the temperature by calculating the external force correction value from the cylinder number and the temperature data.
[0022]
In the present embodiment, the example in which the nonvolatile RAM 130 and the temperature measuring element 131 are provided has been described. However, both of the two devices are not essential, and the effect of each device can be achieved by providing either one. can do.
[0023]
<Example 3>
A third embodiment of the magnetic disk apparatus of the present invention will be described. The basic configuration is almost the same as that described in the section of the prior art, but the magnetic disk device of this embodiment selects two rotational speeds as the steady rotational speed according to the operation mode. The horizontal axis in FIG. 13 is the time axis, and before time 0, the disk is stopped because the magnetic disk device is in the standby state, and the rotation speed is 0 RPM. FIG. 14 is a flowchart in which processing of each process executed by the microprocessor is branched and displayed by recording operation and reproducing operation.
[0024]
When the recording command issuance 101 is performed at time 0 for the magnetic disk device in the standby state, the disk startup processing 103 (Step 4 in FIG. 14) is performed after the short initial processing 102 (Step 3 in FIG. 14). Transition. After the disk rotation speed reaches 4200 RPM (Step 5 in FIG. 14) and the disk start-up completion 121 at the time of recording, seek 105 is performed (Step 6 in FIG. 14), and the completion of settling for the target track is confirmed (FIG. 14). Step 7) and the recording process 106 is performed (Step 8 in FIG. 14). In the prototype magnetic disk, the time from the recording command issue 101 to the recording command end 107 was about 1.6 seconds.
[0025]
Next, a description will be given of processing when the reproduction command issuance 111 is performed on the magnetic disk device in the standby state. Up to the disk activation process 113 is almost the same as the recording command issue 101. However, when the disk rotation speed reaches 3000 RPM (Step 5 in FIG. 14), the disk start completion 122 at the time of reproduction is completed. For this reason, the time required for starting the disk can be shortened as compared with about 1.0 second (1000 ms) and about 1.5 seconds (1500 ms) for issuing the recording command 101. After this, the seek 115 and the reproduction process 116 are continued, and the time from the reproduction command issuance 111 to the reproduction command end 117 is about 1.1 seconds, which can be shorter than the recording command issuance 101 of about 1.6 seconds. It was.
[0026]
As described above, the magnetic disk apparatus according to the present embodiment has two modes of the steady rotational speed of 4200 RPM and 3000 RPM. In the 3000 RPM mode, the time required for the disk startup process can be shortened, but the data transfer rate is reduced to about 70%. In order to eliminate this drawback, as shown in FIG. 15, after receiving the reproduction command issuance 140 and performing the disk startup processing 142 in the mode 1 of 3000 RPM, the function of gradually increasing the disk rotational speed to the mode 2 of 4200 RPM is provided. ing. The acceleration of the disk rotation speed from the mode 1 to the mode 2 is performed more slowly than the rotation acceleration of the disk activation process 142, so that the seeks 143 and 145 and the reproduction processes 144 and 146 can be performed during this period. For this reason, it is possible to reach mode 2 of 4200 RPM without degrading the access performance relating to the reproduction processing. At this time, the clock frequency of the microprocessor is set to 40 MHz in the mode 1 of 3000 RPM and 56 MHz in the mode 2 of 4200 RPM, and when accelerating from the mode 1 to the mode 2, it is increased according to the rotational speed of the disk. As a result, complicated timing adjustment caused by a change in transfer rate can be simplified.
[0027]
The magnetic disk device of this embodiment can improve the access performance when the automatic power down sequence is adopted when issuing a playback command than when issuing a recording command, and achieves both low power consumption and high access performance. A magnetic disk device is realized.
[0028]
【The invention's effect】
The present invention relates to a magnetic disk apparatus having a function of stopping a spindle motor to reduce power consumption. The time from the state where the spindle motor is stopped to the end of data transfer is determined as a recording command process during a playback command process. By making the speed faster than the time, it is possible to realize a magnetic disk device that achieves both improved access performance at the time of a reproduction command and low power consumption.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an example of a schematic configuration of a magnetic disk device.
FIG. 2 is a plan view illustrating an example of a schematic configuration of a magnetic disk device.
FIG. 3 is a schematic view of a part of the magnetic disk device as viewed from above.
FIG. 4 is a diagram for explaining a standby state and an active state of a magnetic disk device.
FIG. 5 is a diagram for explaining the time from when a recording / reproducing command is received until the command execution is terminated in a conventional magnetic disk device;
FIG. 6 is a diagram for explaining the time from the receipt of a recording / reproducing command to the end of execution of the command in the first embodiment of the magnetic disk apparatus of the invention.
FIG. 7 is a flowchart for explaining processing of a recording and reproducing command in the first embodiment of the magnetic disk apparatus of the invention.
FIG. 8 is a schematic diagram showing an example of the configuration of a second embodiment of the magnetic disk device of the invention.
FIG. 9 is a block diagram showing an example of the configuration of a second embodiment of the magnetic disk apparatus of the present invention.
FIG. 10 is a flowchart for explaining a process of rewriting an external force correction value in the second embodiment of the magnetic disk apparatus of the invention.
FIG. 11 is a view for explaining processing for calculating an external force correction value from temperature data in the second embodiment of the magnetic disk apparatus of the invention.
FIG. 12 is a diagram for explaining a serial transfer method in a second embodiment of the magnetic disk device of the invention.
FIG. 13 is a diagram for explaining the time from when a recording / reproducing command is received until the execution of the command is terminated in the third embodiment of the magnetic disk apparatus of the present invention;
FIG. 14 is a flowchart for explaining processing of a recording and reproducing command in the third embodiment of the magnetic disk apparatus of the invention.
FIG. 15 is a diagram for explaining the transition between the rotational speed modes and the change in the clock frequency of the microprocessor in the third embodiment of the magnetic disk apparatus of the present invention;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Head, 12 ... Disk, 13 ... Rotary actuator, 14 ... Voice coil motor, 15 ... Head amplifier, 16 ... Track, 130 ... Nonvolatile RAM, 131 ... Elements for temperature measurement.

Claims (7)

It has a function to reduce power consumption by stopping the spindle motor. When receiving a playback command or recording command for data that transfers the same amount of data, from receiving the playback command to ending the processing of the playback command The magnetic disk device is shorter than the time from when the recording command is received until the processing of the recording command is completed, and in a state where the spindle motor is stopped,
When a data recording command is received, the external force correction value during the recording operation is measured by a dummy seek, the seek operation is performed using the external force correction value during the recording operation, and the recording process is performed.
When a data reproduction command is received, the stored initial value is read as an external force correction value at the time of the reproduction operation, and a seek operation is performed using the external force correction value at the time of the reproduction operation to perform reproduction processing. Magnetic disk unit to be used. Has a memory into the enclosure, the said memory, a magnetic disk drive according to claim 1, wherein the initial value used as an external force correction value at the time of reproduction operation is stored.   3. The magnetic disk device according to claim 2, wherein the memory is a nonvolatile RAM. In the non-volatile RAM, when there is no data recording command is also the initial value used as an external force correction value during reproduction operation, the Rukoto rewritten periodically by an external force correction value when the recording operation measured by the dummy seek 4. The magnetic disk device according to claim 3, wherein 4. The magnetic disk apparatus according to claim 3 , wherein a serial transfer system is used for data input / output of the nonvolatile RAM. 3. The magnetic disk according to claim 2 , wherein an element for temperature measurement is provided in the enclosure, and the initial value of the seek operation during the reproduction operation is calculated based on temperature data output from the element. apparatus. 7. The magnetic disk apparatus according to claim 6 , wherein a serial transfer system is used for data input / output of the temperature measuring element.

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